Create effect where light takes time to reach camera
I don't have a Blender related answer but if you are comfortable coding you can have a look at the OpenRelativity opensource toolkit created at MIT.  There is a demo program available their gamelab website called A Slower Speed of Light.  

Here's the current link.  If the link goes down in the future you are all free to edit this answer.  http://gamelab.mit.edu/games/a-slower-speed-of-light/